﻿def f(n):
    for i in range(2, n):
        if n%i==0:  return False
    return True

cif=['zero','one','two','three','four','five','six','seven','eight','nine']
left=[]
right=[]
s=input()
a=s.split()
b=''
for x in a:
    b+=str(cif.index(x))
b=int(b)
for c in range(1,b):
    if f(c):
        left.append(c)
print(left)
for c in range(b,1015):
    if f(c):
      right.append(c)
print(right)
if (b - max(left)) <= (min(right) - b):
   print(max(left))
elif (b - max(left)) > (min(right) - b):
    print(min(right))